fischerscode/flutter：stable docker 镜像权限问题

Question

docker pull fischerscode/flutter:latest

无法安装、更新和升级图像中的任何内容。只有一个名为 flutter 的用户，但该用户无法执行任何操作。

flutter@2854fb9986fb:/$ cd /root/
bash: cd: /root/: Permission denied
flutter@2854fb9986fb:/$

flutter@2854fb9986fb:/$ apt install clag
E: Could not open lock file /var/lib/dpkg/lock-frontend - open (13: Permission denied)
E: Unable to acquire the dpkg frontend lock (/var/lib/dpkg/lock-frontend), are you root?

如何授予当前用户完全访问权限